Linerless container closure

ABSTRACT

A linerless container closure includes a closure body having a base and an integral skirt extending from the base, retaining means on the skirt engageable with retaining means on a container for releasably securing the closure on the container in sealing relationship, an annular internal sealing surface on the base adjacent the skirt, an integral pressure ring projecting from the base adjacent the radially inner periphery of the sealing surface therearound, and an integral annular sealing flange projecting divergently from the base around the radially inner periphery of the pressure ring and extending radially outwardly across and beyond the pressure ring, the sealing flange being engageable by the sealing rim and the adjacent inside edge of a container neck to clamp the flange between the sealing rim and the base sealing surface and between the inside edge and the pressure ring to thereby form a seal between the container and the closure.

United States Patent [191 Culver [111 3,802,590 [4 1 Apr. 9, 1974 LINERLESS CONTAINER CLOSURE [75] Inventor: Robert M. Culver, Evansville, Ind.

[52] US. Cl. 215/40, 215/DIG. 1 [51] Int. Cl B65d 41/04 [58] Field of Search 215/D1G. 1, 40, 43

[56] References Cited UNITED STATES PATENTS 3,055,526 9/1962 Plunkett 2l5/DlG. 1 3,331,523 7/1967 Exton 215/40 3,232,470 2/1966 Gibson 215/D1G. 1 3,203,571 8/1965 Plunkett 2l5/DIG. l

FOREIGN PATENTS OR APPLICATIONS 1,107,541 I 5/1961 Germany ZIS/DIG. 1 1,213,812 11/1959 France 274,657 9/1969 Austria 215/40 Primary ExaminerDonald F. Norton 5 7] ABSTRACT A linerless container closure includes a closure body having a base and an integral skirt extending from the base, retaining means on the skirt engageable with retaining means on a container for releasably securing the closure on the container in sealing relationship, an annular internal sealingsurface on the base adjacent the skirt, an integral pressure ring projecting from the base adjacent'the radially inner periphery of the sealing surface therearound, and an integral annular sealing flange projecting divergently from the base around the radially inner periphery of the pressure ring and extending radially outwardly across and beyond the pressure ring, the sealing flange being engageable by the sealing rim and the adjacent inside edge of a container neck to clamp the flange between the sealing rim and the base sealing surface and between the inside edge and the pressure ring to thereby form a seal between the container and the closure.

13 Claims, 5 Drawing Figures 1 LINERLESS CONTAINER CLOSURE BACKGROUND OF THE INVENTION The invention relates to container closures, more particularly, to linerless closures, that is, closures requiring no liner or gasket to effect a seal with a container.

Linerless container closures that will effect a tight seal with a container are in demand, for markedly reducing the closure cost, and for sanitary, assembly and other reasons. Heretofore, a number of such closures have been proposed but have been lacking in one or more respects. The principal problem has been the provision of a closure that will reliably seal a container, especially such containers as commonly suffer from surface irregularities. Sealing problems have been greatest with glass bottles used to package alcoholic or oily liquids.

'A linerless container closure previously employed with a particular glass container design is illustrated in Miller et al. US. Pat. No. 3,255,909. This combination of closure and container requies that the container be specially'manufactured for use with the closure, with the container neck held to close tolerances, all rendering the container relatively expensive. Other prior linerless closures were unsuccessful in sealing glass containers and/or were expensive to manufacture, with the result that, apparently, none of them are used to a significant extent with glass containers, and especially, for packaging alcoholic or oily liquids.

It would be desirable to provide a linerless container closure that would reliably seal containers having common irregularities, especially standard articles of commerce including glass bottles. More particularly, it would be desirable for achieving and maintaining reliable sealing to provide a closure that affords an increased area of firm sealing engagement between the closure and a container, and, further, produces a tighter, more lasting seal. Also, it would be desirable to provide such a closure that could be manufactured readily and economically, and, further, could take advantage of the potential manufacturing ease and economy afforded by plastic materials of construction.

SUMMARY OF THE INVENTION The invention provides a linerless container closure including a closure body having a base and an integral skirt extending from the base, retaining means on the skirt engageable with retaining means on a container for releasably securing the closure on the container in sealing relationship, an annular internal sealing surface on the base adjacent the skirt, an integral pressure ring projecting from the base adjacent the radially inner periphery of the sealing surface therearound, and an integral annular sealing flange projecting divergently from the base around the radially inner periphery of the pressure ring and extending radially outwardly across and beyond the pressure ring, the sealing flange being engageable by the sealing rim and the adjacent inside edge of a container neck to clamp the flange between the sealing rim and the base sealing surface and between the inside edge and the pressure ring to thereby form a seal between the container and the closure. The closure advantageously is constructed of molded plastic, preferably a polyolefin. The invention also provides a new and improved combination of a container and the closure.

The container closure of the invention performs outstandingly inproviding a reliable seal on a container. Leakproof sealing is achieved on glass bottles filled with alcoholic or oily liquids. For example, the new closure reliably seals glass bottles that are manufactured commercially with GCMI (Glass Container Manufacturers Institute) tolerances, and which commonly have irregularities on the rim or on the adjacent inside edge or so-called inside top radius of the bottle neck. Sealing is effected both on the rim and on the inside edge, which may be a radiused edge or a chamfered edge, as conventionally provided. It is a feature of the preferred embodiments of the invention that, owing to the construction of the closure, an integral sealing flange thereof is stretched over the inside edge of the container neck, to completely fill and tightly seal irregularities on the surface of the neck.

The construction of the new container closure is also advantageous in that the pressures exerted in use act to prevent the closure from backing off of the container, which may occur with other closures, especially upon moving or handling. Also, there is no loss of the seal upon normal relaxation of the closure construction material. The closure continues to be effective when used for rescaling a container subsequent to its initial application and removal.

The new closure is useful both for pressurized and unpressurized containers, constructed of'various materials, including glass, plastic and metal. The closure may be manufactured readily and economically of molded plastic, preferably polyolefin, and the physical properties of the plastic, including appropriate rigidity, flexibility, resilience, cold flow and deformability are utilized to advantage.

DESCRIPTION OF THE DRAWINGS The attached drawings illustrate preferred embodiments of the invention, without limitation thereto. In the drawings, like elements are identified by like reference symbols in each of the views, and:

' FIG. 1 is an exploded or disassembled longitudinal sectional view of a linerless container closure according to the invention and the outer portion of the neck of a container with which the closure may be employed, taken along the common longitudinal axis of the articles;

FIG. 2 is an elevational and partly sectional view of the. members illustrated in FIG. 1, showing them in assembled relationship;

FIG. 3 is an enlarged fragmentary longitudinal sectional view of the members illustrated in the preceding views, showing the closure as it is being threaded onto the container neck and prior to reaching sealing interengagement of the members;

FIG. 4 is a view similar to FIG. 3, but illustrating the closure tightly threaded on the container neck, as f1- nally assembled in sealing interengagement; and

FIG. 5 is a view similar to FIGS. Sand 4, but illustrating another form of container neck to which the closure may be applied, and illustrating in full lines the container neck as it appears when the closure is being applied prior to reaching sealing engagement, and in broken lines the container neck as it appears when the closure is finally applied in sealing engagement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1-4 of the drawings, a linerless container closure or cap 10 is illustrated in combination with the neck 12 of a glass bottle or container, in accordance with a preferred embodiment of the invention. In FIG. 5, the closure 10 is illustrated in combination with a bottle neck 12 constituting a modification or variation of the bottle neck 12 illustrated in the preceding views.

The illustrative bottle necks 12 and 12 embody conventional finishes, such as are provided on commercial 4/5 quart liquor bottles. In each case, the finish includes an annular external transfer ring 14, an external screw thread 16 thereabove, and a top sealing finish 18 or 18'. The top sealing finish 18 of the bottle neck of FIGS. 1-4 includes a generally flat normally horizontal sealing rim 20 and an adjacent radiused inside or inner edge 22, also referred to at times as the inside top radius. The sealing rim constitutes the outer or upper end surface of the bottle neck 12. The inside edge 22 extends from the rim 20 to the inner wall 24 of the bottle neck 12, and defines the mouth of the bottle neck. The top sealing finish 18 of the bottle neck 12' illustrated in FIG. similarly includes a generally flat sealing rim 26 and a chamfered inside or inner edge 28 extending from the-rim 26 to the inside wall 24 of the bottle neck and defining the mouth thereof.

The neck 12 or 12 ofa glass bottle as manufactured for commercial use within acceptable tolerances frequently suffers from irregularities on its rim 20 or 26 and on its inside edge 22 or 28. In order to produce a liquid-tight seal, itis necessary for the closure to accommodate the irregularities, and especially, to tightly and completely fill in any depressions. A tight seal should be produced both upon initial application of the closure to the container and upon rescaling after opening the container. The seal should not be broken upon standing or handling, as a result of relaxation of the sealing members or backing off of the closure.

The closure is constructed to cooperate with bottles having the conventional necks 12 and 12, without need for any special construction or finishing of the bottle neck. The closure itself is readily and economically manufactured by molding. In general, the closure 10 is constructed to fit a bottle neck or other container neck of predetermined size and dimensions, but the closure-structure accommodates a certain amount of variation in neck dimensions.

In the preferred embodiments of the invention, the closure 10 is molded as a unit of plastic material suitable for performing the intended functions. As will appear from the description which follows, the material should be sufficiently rigid to form a closure body and produce the necessary pressure, yet sufficiently flexible in an appropriate thickness to form a pliable sealing element. The material should provide for cold flow or deformation of thesealing element, to accommodate irregularities in the container neck. The material while somewhat resilient preferably also has a relatively poor elastic memory, so as to minimize any tendency for the sealing element to cause the closure to back off of the container neck. The closure 10 may be constructed of a polyolefin, as conventionally used for the manufacture of prior container closures. The preferred material of construction is a polymer of propylene and/or ethylene, including polypropylene, polyethylene, and copolymers of propylene and ethylene. Polypropylene is employed in the preferred illustrative embodiment.

The closure 10 includes a body 30 having a circular base or panel 32 and a cylindrical tubular skirt 34 extending around the outer periphery of the base 32 and normal thereto. An inner wall 36 of the skirt 34 is provided with an integral molded screw thread 38. The base 32, the skirt 34, and the thread 36 in general may be of conventional construction, so that the body 30 is relatively rigid and the structure is capable of forming a tight, strong and durable closure. The screw thread 38 mates with the screw thread 16 on the bottle neck 12 or 12. The screw threads 16 and 38 serve as interengageable retaining means for releasably securing the closure 10 on the bottle neck in sealing relationship.

The base 32 of the closure 10 includes a substantially flat inner wall 40. A relatively rigid integral circular pressure ring 42 having a relatively shallow substantially V-shaped cross section projects from the inner wall 40 of the base, in spaced relation to the inner wall 36 of the closure skirt 34. As clearly seen in FIGS. 3 and 4, the pressure ring 42 includes inclined radially outer and inner surfaces 44 and 46 extending at respective angles A and B of 45 to the longitudinal axis of the closure 10, thus enclosing an angle of between them, in the illustrative preferred embodiment. The respective surfaces 44 and 46 of the pressure ring are joined to the inner wall 40 of the closure base 32 by fillets 48 and 50. The pressure ring surfaces 44 and 46 are of equal width, and the altitude of the triangle formed by the surfaces with the inner wall surface 40 is parallel to the longitudinal axis of the closure 10, which in use normally is vertical. The pressure ring surfaces 44 and 46 intersect oradjoin around a circular ridge, peak or apex 52.

An annular internal flat sealing surface 54 remains on the inner wall 40 of the closure base 32, and it extends from the inner wall 36 of the skirt 34 to the fillet 48 adjoining the outer surface 44 of the pressure ring 42. The pressure ring 42 bounds the base sealing surface 54, projecting from the base 32 adjacent the radially inner periphery of the sealing surface 54 therearound.

An integral frusto conical, annular sealing flange or fin 56 capable of cold flow or deformation projects divergently from the inner wall 40 of the base 32 around the radially inner periphery of the pressure ring 42 and spaced inwardly from the inner surface 46 thereof. The sealing flange 56 is a relatively thin and flexible element having respective inclined radially outer and inner surfaces 58 and 60, which converge slightly in a direction away from the base 32 and thereby form a slightly tapered element. The flange outer and inner surfaces 58 and 60 extend at respective angles C and D of 40 and 46 with respect to the longitudinal axis of the closure 10. The respective surfaces 58 and 60 are joined to the inner wall 40 of the base 32 by fillets 62 and 64. The flange 56 extends from the base 32 radially outwardly across and beyond the pressure ring 42, with the free end 66 of the flange adapted to extend over or reach the base sealing surface 54 for sealing purposes, as illustrated in FIG. 4.

The sealing flange 56 is adapted to flex around the pressure ring 42 and intimately follow the outer surface 44 of the pressure ring, the adjacent fillet 48, and the base sealing surface 54, to form a seal therewith, as seen in FIG. 4. An annular air pocket 68 then may remain between the base of the sealing flange 56 and the inner surface 46 of the pressure ring 42. At times, the sealing flange 56 is pulled so tightly against the pressure ring 42 that the pocket 68 is eliminated or substantially Referring to FIG. 3, the sealing flange 56 projects obliquely into the path of relative movement of the bottle neck 12 as the closure is threaded onto the neck. The sealing flange 56 is contacted by the neck 12, more specifically, by the rim thereon. As the closure 10 is threaded onto the neck 12, the flange 56 is moved or displaced by the neck upwardly into interengagement of the several elements as illustrated in FIG. 4. The sealing rim 20 and the adjacent inside edge 22 of the container neck 12 clamp the sealing flange 56 between the sealing rim 20 and the base sealing surface 54, and between the inside edge 22 and the outer surface 44 of the pressure ring 42, to thereby form a seal between the neck 12 of the container and'the closure 10. The seal extends over the rim 20 and over the adjacent inside edge 22, to seal the neck in the two significant areas. The rigidity of the pressure ring 42 and of the closure base 32 cause the sealing flange 56 to cold flow or deform into any surface irregularities on the sealing rim 20 or inside edge 22 of the bottle neck. With both the rim 20 and inside edge 22 areas sealingly engaged, the possibility of a leak due to an imperfection in either is effectively foreclosed.

his an important feature of the preferred embodi- I ments of the invention that the structure of the closure 10 functions additionally to stretch the sealing flange 56 over the inside edge 22 of the bottle neck 12, or over a portion thereof, so that the sealing flange conforms very tightly to the surface of any irregularity in the edge of the bottle neck, to form an exceptionally tigh't,'relia ble seal. The stretching of the sealing flange takes place when the portion of the sealing flange adjacent its free end 66 is clamped between the bottle neck rim 20 and the base sealing surface 54, and the pressure ring 42 moves inwardly with respect to the inside edge 22 on the bottle neck, whereby the intermediate portions of the sealing flange 56, clamped between the pressure ring 42 and the inside edge 22, are stretched or pulled inwardly and downwardly. This result is obtained upon applying sufficient torque to the closure 10, for example, about 25-30 lbs. for the illustrative embodiment. The seal is maintained despite relaxation of the stressed closure material.

The closure 10 cooperates with the bottle neck 12' of FIG. 5 in essentially the same manner. Thus, as the bottle neck 12 is received within the closure 10, the sealing rim 26 contacts the free end 66 of the sealing flange 56, and with further relative movement, the elements become interengaged in the manner illustrated in broken lines. At this time, the sealing flange 56 is clamped between the sealing rim 26 and the base sealing surface 54, and between the chamfered inside edge tleneck 12 or 12 is stretched over the rim 20 or 26 and the inside edge 22 or 28 thereof. Sealing forces are exerted both in parallel to the longitudinal axis of the bottle neck, betweenthe sealing rim '20 or 26 and the base sealing surface 54, and angularly or obliquely with respect to such axis, between the inside edge 22 or 28 and the outer surface 44 of the pressure ring 42. The forces exerted by the pressure ring 42 angularly in the direction of the inside edge 22 or 28 tend to prevent the closure 10 from backing off, particularly as compared to the axial or vertical forces exerted if, for example, only a resilient sealing or gasket member were inserted between the sealing rim 20 or 26 of a bottle neck and the base sealing surface 54 of the closure.

The closure 10 is constructed in appropriate size and with an appropriate screw thread 38 to receive the bottle neck 12 or 12 or other container neck therein. While it is preferred to provide on the container neck and on the closure mating screw threads 16 and 38, as illustrated, it will be apparent that other interengageable retaining means may be provided on the respective members for securing them together.

The diameter of the ridge 52 of the pressure ring 42 is determined for the container neck to be used with the closure. Thus, the diameter of the ridge 52 is less than the outer diameter of the inside edge 22 or 28, or less than the inner diameter of the rim 20 or 26, of the bottle neck 12 or 12'. The sealing flange 56 is spaced inwardly from the pressure ring 42, in the manner illustrated, with permissible variation in spacing. Some variation in the inside diameter of the inner wall 24 of the bottle neck 12 is acceptable, so long as the ridge 52 of the .pressure ring 42 is within the outside diameter of the inside edge 22. With greater variation,the diameter of the ridge 52 may be increased or decreased with or without a change in the diameter of the sealing flange 56, as may be necessitated by a change in the diameter of the ridge 52 or for molding facility or other reason. It is relatively simple and economical to change a mold to vary the location of the pressure ring 42, and this represents an advantage of the invention. The closure 10 similarly is constructed for cooperation .with the 1 bottle neck 12'. In certain cases, as with the respective illustrative embodiments, the closure 10 maybe used alternatively with conventional bottles of either type.

Illustrative typical dimensions for a bottle neck 12 or 12 include a diameter for the inner 'wall 24 of 0.760 inch and a diameter for the outer wall 70, adjacent to the rim 20 or 26, of 0.978 inch. The inside edge 22 of the container neck 12 has a radius R of about 0.031 inch and an outer diameter of about 0.822 inch. The inside edge 28 of the container neck 12' extends at an angle of about 45 to the longitudinal axis of the bottle neck 12 and has an outer diameter of 0.830 inch.

Referring to FIGS. 3 and 4, the thickness E of the base 32 in the illustrative embodiment is 0.060 inch, and the altitude F of the pressure ring 42 is 0.025 inch. The diameter of the ridge 52 of the pressure ring is 0.815 inch. The diameter of the inner wall 36 of the closure skirt 34, exclusive of the screw thread 38, is 0.982 i 0.012 inch.

The horizontal distance G from the outer fillet 62 adjacent the sealing flange 56, to the ridge 52 of the pressure ring is 0.055 inch in the illustrative embodiment. The horizontal distance H from the fillet 62 to the free end 66 of the sealing flange 56 is 0.120 inch. The vertical distance J from the free end 66 of the sealing flange 56 to the inner wall 40 of the base 32 is 0.1 10 inch. The sealing flange 56 is 0.010 inch thick at its free end 66, and 0.012 inch at its juncture with the base inner wall 40, measured in the direction parallel to the wall 40 and exclusive of the fillets 62 and 64.

The invention thus provides a linerless closure that reliably seals a container in liquid-tight engagement therewith. The closure seals standard containers manufactured with normal tolerances and having the common irregularities in the finish. Glass containers are effectively sealed, with no necessity for special molding, finishing or other techniques to provide a reliable sealing surface. The seal is maintained even with the more difficult alcohol and oil-containing liquids. The new closure provides for sealing engagement both with the sealing rim of a container neck and with the inside edge thereof, whether it be radiused or chamfered. The preferred embodiments of the closure further cooperate with the container neck to stretch a sealing flange over and tightly against the surface of the inside edge of the bottle neck, in intimate leak-proof engagement therewith.

The new closure is readily and economically molded in one piece of plastic material. A single closure may be employed with a number of containers of variable neck dimensions, and the sealing elements of the closure may be manufactured to cooperate with container necks having greater variations in dimension. The closure will continue to function effectively as the container mold wears normally, with resulting changes in the contour of the container neck, particularly the inside edge thereof.

While preferred embodiments of the invention have been described and illustrated, it will be apparent to those skilled in the art that various changes and modifications may be made therein within the spirit and scope of the invention. It is intended that such changes and modifications be included within the scope of the appended claims.

Having thus described the invention what 1 claim as new and desire to secure by letters patent is:

l. A linerless container closure which comprises:

a closure body having a base and an integral skirt extending from the base,

retaining means on said skirt engageable with retaining means on a container for releasably securing the closure on the container in sealing relationship,

an annular internal sealing surface on said base adjacent said skirt,

an integral pressure ring projecting from said base adjacent the radially inner periphery of said sealing surface therearound, and

an integral annular sealing flange projecting divergently from said base around the radially inner periphery of said pressure ring and extending radially outwardly across and beyond the pressure ring, the free end of said sealing flange being adapted to extend over said base sealing surface for sealing purposes,

said sealing flange being engageable by the sealing rim and the adjacent inside edge of a container neck to move the flange into intimate contact with the radially outer surface of said pressure ring and also with said base sealing surface, whereby upon tightening the closure on a container, said flange is sealingly clamped both between the sealing rim and the base sealing surface with the application of sealing force in parallel to the container axis, and between the inside edge and the outer surface of the pressure ring with the application of sealing force angularly with respect to the container axis.

2. A closure as defined in claim 1 wherein said pressure ring is a relatively rigid element having an inclined an annular internal flat sealing surface on said base adjacent said skirt,

a relatively rigid integral pressure ring having a substantially V-shaped cross section projecting from said base adjacent the radially inner periphery of said sealing surface therearound, and

a relativelyflexible integral annular sealing flange capable of cold flow projecting divergently from said base around the radially inner periphery of said pressure ring and spaced therefrom, and extending radially outwardly across and beyond the pressure ring, the free end of said sealing flange being adapted to extend over said base sealing surface for sealing purposes,

said sealing flange being engageable by the sealing rim and the adjacent inside edge of a container neck to move the flange into intimate contact with the radially outer surface of said pressure ring and also with said base sealing surface, whereby upon tightening the closure on a container, said flange is sealingly clamped both between the sealing rim and the base sealing surface with the application of sealing force in parallel to the container axis, and between the inside edge and the outer surface of the pressure ring with the application of sealing force angularly with respect to the container axis, and said flange is stretched over the inside edge.

5. A closure as defined in claim 4 and constructed of molded polyolefin.

6. A closure as defined in claim 5 wherein said polyolefin is polypropylene.

7. A closure as defined in claim 4 and wherein said skirt retaining means comprise screw thread means.

8. A-container and closure therefor comprising, in

combination,

a container having a neck provided with external retaining means and terminating in a sealing rim and an adjacent inside edge; and

a linerless container closure which comprises:

a closure body having a base and an integral skirt extending from the base, said skirt receiving said container neck therein,

retaining means on said skirt engageable with said retaining means on said container neck for releasably securing the closure on the container in sealing relationship,

an annular internal sealing surface on said base adjacent said skirt,

an integral pressure ring projecting from said base adjacent the radially inner periphery of said sealing surface therearound, the ridge of said pressure ring having a diameter less than the outer diameter of said inside edge of said container neck, and

an integral annular sealing flange projecting divergently from said base around the radially inner periphery of said pressure ring and extending radially outwardly across and beyond the pressure ring, the free end of said sealing flange being adapted to extend over said base sealing surface for sealing purposes;

said sealing flange being engageable by said sealing rim and said inside edge of said container neck to move the flange into intimate contact with the radially outer surface of said pressure ring and also with said base sealing surface, whereby upon tightening the closure on said container, said flange is sealingly clamped both between the sealing rim and the base sealing surface with the application of sealing force in parallel to the container axis, and

between the inside edge and the outer surface of the pressure ring with the application of sealing force angularly with respect to the container axis, and said flange is stretched over the inside edge. 9. A combination as defined in claim 8 and wherein said closure is constructed of molded plastic, said pressure ring is a relatively rigid element having a substantially V-shaped cross section, and said sealing flange is a relatively flexible element capable of cold flow and is spaced from the inner periphery of said pressure ring.

wherein said plastic is polypropylene. 

1. A linerless container closure which comprises: a closure body having a base and an integral skirt extending from the base, retaining means on said skirt engageable with retaining means on a container for releasably securing the closure on the container in sealing relationship, an annular internal sealing surface on said base adjacent said skirt, an integral pressure ring projecting from said base adjacent the radially inner periphery of said sealing surface therearound, and an integral annular sealing flange projecting divergently from said base around the radially inner periphery of said pressure ring and extending radially outwardly across and beyond the pressure ring, the free end of said sealing flange being adapted to extend over said base sealing surface for sealing purposes, said sealing flange being engageable by the sealing rim and the adjacent inside edge of a container neck to move the flange into intimate contact with the radially outer surface of said pressure ring and also with said base sealing surface, whereby upon tightening the closure on a container, said flange is sealingly clamped both between the sealing rim and the base sealing surface with the application of sealing force in parallel to the container axis, and between the inside edge and the outer surface of the pressure ring with the application of sealing force angularly with respect to the container axis.
 2. A closure as defined in claim 1 wherein said pressure ring is a relatively rigid element having an inclined radially outer surface, and said sealing flange is a relatively flexible element capable of cold flow.
 3. A closure as defined in claim 1 and constructed of molded plastic.
 4. An integrally molded linerless plastic container closure which comprises: a closure body having a base and an integral skirt extending from the base, retaining means on said skirt engageable with retaining means on a container for releasably securing the closure on the container in sealing relationship, an annular internal flat sealing surface on said base adjacent said skirt, a relatively rigid integral pressure ring having a substantially V-shaped cross section projecting from said base adjacent the radially inner periphery of said sealing surface therearound, and a relatively flexible integral annular sealing flange capable of cold flow projecting divergently from said base around the radially inner periphery of said pressure ring and spaced therefrom, and extending radially outwardly across and beyond the pressure ring, the free end of said sealing flange being adapted to extend over said base sealing surface for sealing purposes, said sealing flange being engageable by the sealing rim and the adjacent inside edge of a container neck to move the flange into intimate contact with the radially outer surface of said pressure ring and also with said base sealing surface, whereby upon tightening the closure on a container, said flange is sealingly clamped both between the sealing rim and the base sealing surface with the application of sealing force in parallel to the container axis, and between the inside edge and the outer surface of the pressure ring with the application of sealing force angularly with respect to the container axis, and said flange is stretched over the inside edge.
 5. A closure as defined in claim 4 and constructed of molded polyolefin.
 6. A closure as defined in claim 5 wherein said polyolefin is polypropylene.
 7. A closure as defined in claim 4 and wherein said skirt retaining means comprise screw thread means.
 8. A container and closure therefor comprising, in combination, a container having a neck provided with external retaining means and terminating in a sealing rim and an adjacent inside edge; and a linerless container closure which comprises: a closure body having a base and an integral skirt extending from the base, said skirt receiving said container neck therein, retaining means on said skirt engageable with said retaining means on said container neck for releasably securing the closure on the container in sealing relationship, an annular internal sealing surface on said base adjacent said skirt, an integral pressure ring projecting from said base adjacent the radially inner periphery of said sealing surface therearound, the ridge of said pressure ring having a diameter less than the outer diameter of said inside edge of said container neck, and an integral annular sealing flange projecting divergently from said base around the radially inner periphery of said pressure ring and extending radially outwardly across and beyond the pressure ring, the free end of said sealing flange being adapted to extend over said base sealing surface for sealing purposes; said sealing flange being engageable by said sealing rim and said inside edge of said container neck to move the flange into intimate contact with the radially outer surface of said pressure ring and also with said base sealing surface, whereby upon tightening the closure on said container, said flange is sealingly clamped both between the sealing rim and the base sealing surface with the application of sealing force in parallel to the container axis, and between the inside edge and the outer surface of the pressure ring with the application of sealing force angularly with respect to the container axis, and said flange is stretched over the inside edge.
 9. A combination as defined in claim 8 and wherein said closure is constructed of molded plastic, said pressure ring is a relatively rigid element having a substantially V-shaped cross section, and said sealing flange is a relatively flexible element capable of cold flow and is spaced from the inner periphery of said pressure ring.
 10. A combination as defined in claim 9 and wherein said respective retaining means comprise screw thread means.
 11. A combination as defined in claim 10 and wherein said inside edge on said container neck is a radiused edge.
 12. A combination as defined in claim 10 and wherein said inside edge on said container neck is a chamfered edge.
 13. A combination as defined in claim 10 and wherein said plastic is polypropylene. 